Process for making lead sulphate



Patented Mar. 4, l l. v l i fi r l ld f PHILIP ALEZQANDEB MACKAY, OF LONDON, ENGLAND.

PROCESS FOB. MAKENG- LEAD SULPHATE.

N Drawing. Application filed September 28, 1920. Serial No. 413,418.

To all whom it may concern: may advantageously be done by treating the Be it known that PHILIP ALEXANDER cast lead with a solution of sulphate of MAOKAY, a citizen of the United States of mercury, or copper sulphate, after which America, residing at London, England, has the lead is treated by dissolving it in oleum ii invented an Improved Process for Making at a temperature of about 90 centigrade, the Lead Sulphate, of which the following is a oleum being preferably in excess so that the specification. reaction may be quicker, since the presence This invention relates to an improved of the excess oleum prevents the mass get process for making lead sulphate direct ting too thick and thereby retarding the 10 from metallic lead. reaction.

In the manufacture of lead sulphate it Having started the reaction by providing is known that when metallic lead is heated the external temperature of 90 centigrade with strong sulphuric acid to some 260 I have found that it may proceed without centigrade it is suddenly converted into sulthe application of any other heat until all 1 phate of lead. This temperature, however, the lead has been converted into lead sulis so high that much of the acid would have phate forming the lead pigment which is volatilized before the temperature was required, and after the start of the reacreached which is very wasteful of acid, and tion no further external heat need be apit would be difficult to obtain materials of plied; the exothermic heat is more than 20 construction which. will stand. the high. temsufficient to complete the reaction. In ad .i-

perature mentioned without rapid deterioration, therefore, to the saving of acid by the tion. use of a low temperature only, when the lead The object of this invention is to obviate is amalgamated on the surface with merthese difficulties and to obtain lead pigment cury, or in contact with mercury, copper, or 25 by a process involving comparatively low silver, it is also possible easily to find matetemperatures only. rials of construction in which the process In the course of experiment I have found can take place, for instance, it may be carthat lead may be dissolved with oleum at ried out in a porcelain vessel, and in the a comparatively low termperature, and this case of the treatment with a more electro- 30 invention consists in the use of oleuir for negative element the application of heat the very rapid solution of commercialflead needs only to be for a short time. at a temperature of not more than about When carrying my invention into prac- 150 centigrade. If started at this temtice, I prefer to treat commercial lead with perature after the reaction has started it one-and-a-half to two parts of its weight 35 may in many cases proceed withoutthe apof oleunnand after the completion of its phcation of further heat until. all the lead reaction the oleum is diluted to precipitate has been converted into sulphate, or at any the lead sulphate and then excess oleuin rerate it can proceed at a reduced temperature, covered comparatively pure as a weaker say, at about 100 centigrade. Further, by acid. 40 the treatment of the lead with oleum in the Before submitting the lead. to the action presence of a more electromegative element of oleum I coat the lead with an element than lead, such, for example, as mercury, electro-negative to it, or alternatively ll copper, or silver, it is found that the lead introduce the latter into the oleum during will go into solution at even lower ten'iperathe reaction, either in the form of a metal 1 0 45 tures, i. e., between to Centigrade, or its chlorides, sulphates or nitrates.

and. with a most violent exothermic reac- An additional advantage of this process tion. is that when the lead contains bismuth or Metals of the character of mercury, copsilver the oleum forms a solvent for the per or silver. are employed in this treatbismuth or silver which are in solution after 50 ment. although it isunderstood that other the lead sulphate has been precipitated, and

elements which are electro-negative to lead may be recovered by any suitable known can be employed. process, thus a considerable further saving In carrying out this process, therefore, it is achieved.

is preferable that the metallic lead is first I claim 56 treated by covering it with a slight coating 1. Method of manufacturing lead sulphate of a more electro-negative element, which from metallic lead, wherein the metallic lead is subjected to the action. of oleum until all the metallic lead is converted into sulphate.

2. Method of manufacturing lead sulphate from metallic lead, wherein the metallic lead is subjected to the action of oleum at a temperature. not exceeding 150 Centigrade and the reaction maintained at a temperature of about 100 centi rade until all the metallic lead is converted into sulphate.

3. Method of manufacturing lead sulphate from metallic lead, wherein the metallic lead is subjected to the action of oleum in the presence of a metal electro-negatiye to lead, until all the metallic lead is converted into sulphate.

Method of manufacturing lead sulphate from metallic lead. wherein the metallic lead is subjected to the action of oleum at a temperature between 95 to 100 centi grade in the presence of a metallic element electro-negative to lead, until all the metallic lead is converted into sulphate.

Method of manufacturing lead sulphate from metallic lead, wherein the metallic leal is coated with metallic element electronegative to lead, and then subjected to the action of oleum until all the metallic lead in converted into sulphate.

6. Method of manufacturing lead sulphate from metallic lead wherein the metallic lead is coated with a metallic seating elect-ro-negatiye to lead and then subjected to the action of olcum at a temperature between 05 and 100 centigrade until all the metallic lead is converted into sulphate.

7. lllGtlIOd of manufacturing lead sulphate 11cm metallic leach wherein, the metallic lead is treated with a solution of a sa t of a metallic element elecho-negative to lead, and capable of forming a coating, and then sub jccted to the action of oleuni until all the metallic lead is converted into sulphate.

8. Method of manufacturing lead sulphate from metallic lead, wherein the metallic lead is treated with a solution of a salt of a metallic element electromegative to lead, and capable of forming a coating and then subjected to the action of oleum at a temperature between 95 and 100 centigrade until all the metallic lead is converted into sulphate.

9. A method of manufacturing lead sulphate from metallic lead, wherein the metallic lead is subjected to the action of oleum in excess of the amount of oleum necessary to cissolve the metallic lead whereby the required temperature is obtained by exothermic reaction.

10. A method of manufacturing lead sulphate from metallic leach herein the metallie lead is subjected to the action of oleum in excess of the amount of oleum necessary to dissolve the metallic lead in the presence of a metal. electro-negative to lead whereby the required temperature is obtained by eX- othermic reaction.

11. A method of manufacturing lead sul phate from metallic lead. wherein the metallic lead coated with a metallic element electrone tire to lead and then subjected I 'i in excess of the oleum required to dissolye the metallic lead wherey the rc uired tiperature is obtained by lic lead i. t n of a salt of a nu ative to lead and ca .e mine" a coating, and th 'jcctei'l to the action of oleum in excess of ol 'iin rcouired to dissolve the metallic i he required temperature is obeimthermia: reaction. 7 rod of manufacturing lead sulpirate from metallic lead at a teiinperature of about 90 ceritignfatle. wherein the state of the metallic lead is changed by utilizing ermic reaction obtained by subjecting metallic lead to the action of oleum in ,1 e of the oleum required to dissolve the tic lea: and in the presence of a metal electarr-negative to lead, all as se forth.

in testimony whereof affix my signature.

PHILIP ALEXANDER EVIAOKAY. il itness:

Lnwis B. B. SPARKS. 

